Princess Diana and Dodi Fayed together picked out the diamond ring he gave her hours before they died, according to the jeweler who sold them the ring -- but who has not been paid for it.

Alberto Repossi said in a telephone interview today that the couple came into the Monaco branch of his store unexpectedly about 10 days before the Aug. 30 auto accident that killed them. The couple was vacationing on the Riviera at the time.

They spent only about four or five minutes in the store, Repossi said, because they already knew which ring they wanted. They had seen it in a Repossi advertisement in the September edition of a fashion magazine, L'Officiel de la Couture et de la Mode de Paris.

Neither Diana nor Fayed said anything in the store about becoming engaged, Repossi said, contrary to initial press reports. But marriage was the theme of the ad for the ring, and it was designed as an engagement ring.

"Tell me yes!" was the headline on the ad, which featured only one ring in a large picture. "A little yes for the most beautiful day of your life. It was worth waiting for!"

Repossi said it was he who designed the ring, contrary to press reports that Fayed had done so. It had been in his store since May and was the top of a line of engagement jewelry modeled after the "cocktail rings" of the 1930s, he said.

The picture shows an emerald-cut diamond surrounded by four triangle-shaped diamonds atop a thick band encrusted with smaller diamonds. Repossi declined to specify the size in carats of the principal diamond or the price of the ring, which press reports have put at more than $200,000. After a size alteration, Fayed picked it up at Repossi's Paris store, on the same square as the Ritz Hotel, about 6 p.m. Saturday Aug. 30. "He said he loved it and he was certain the princess would love it as well," Repossi said.

Just over six hours later, the Mercedes that was taking them from the Ritz to Fayed's apartment slammed into a concrete pillar in a highway tunnel along the Seine River. The car was traveling at between 93 and 112 mph, a Paris police official told the Reuter news agency today, in the first authorized statement on the speed of the vehicle.

Fayed and the driver, Henri Paul, a Ritz employee, were killed instantly. Diana was pronounced dead in a hospital 3 1/2 hours later. A bodyguard, Trevor Rees-Jones, is hospitalized with facial and other injuries. The British Embassy here said today that Rees-Jones underwent surgery for 10 hours last week and is recovering but will not be able to speak to investigators for some time.

Police have placed nine photographers and a motorcycle driver who were at the scene of the crash under investigation for involuntary homicide and failing to aid victims of an accident -- a step short of criminal charges. Recent press reports have said police checks of the photographers' cellular phones indicate they did not try to summon help after the crash, as some said they did.

Police also have said that Paul, an assistant security chief at the Ritz who was called in to drive at the last minute, had three times the legal limit of alcohol in his system. His family has asked police to perform another test, but results have not yet been released.

Repossi declined to say if he had sold other pieces of jewelry to Fayed or Diana. Michael Cole, spokesman for Mohamed Fayed, Dodi's father, said last week that the pair had exchanged gifts: a silver plaque inscribed with a love poem from Dodi to Diana, a gold cigar clipper from Diana to Dodi with a gold tag inscribed "With love from Diana," along with a pair of cuff links that had belonged to her father, the eighth Earl Spencer.

The ring reportedly was found in the wreckage of the Mercedes and given to Diana's sisters when they came to Paris to accompany her body back to England. Repossi said the ring came to light only because his insurance policy requires him to file a claim within 24 hours for losses, and, despite the circumstances, he felt he had to do so since he had not been paid.

"Someone at Lloyd's {the insurance company} must have told the press," Repossi said. "I would never have spoken of the ring if it had not already been revealed. My pain does not permit me to rejoice in the publicity." CAPTION: Diana and Dodi Fayed reportedly picked out this ring after seeing it advertised in a magazine.